US Steel Grade Comparison — A36 vs A992 vs A572-50 vs A588 vs A500
Side-by-side comparison of all major US structural steel grades. A36, A992, A572 Grade 50, A588, A500 Grade B, A500 Grade C, and A1085 yield strength, tensile strength, weldability, cost, and application guidance. When to use which grade for beams, columns, plates, HSS, and connections.
Quick access: A36 Steel → | A992 Steel → | A572 Grade 50 → | All US Steel Grades →
Side-by-Side Property Comparison
Mechanical Properties
| Grade | Fy (ksi) | Fu (ksi) | Fy (MPa) | Fu (MPa) | Fy/Fu | E (ksi) |
|---|---|---|---|---|---|---|
| A36 | 36 | 58 | 248 | 400 | 0.62 | 29,000 |
| A572 Gr 42 | 42 | 60 | 290 | 415 | 0.70 | 29,000 |
| A992 | 50 | 65 | 345 | 450 | 0.77 | 29,000 |
| A572 Gr 50 | 50 | 65 | 345 | 450 | 0.77 | 29,000 |
| A588 | 50 | 70 | 345 | 485 | 0.71 | 29,000 |
| A500 Gr B | 46 | 58 | 317 | 400 | 0.79 | 29,000 |
| A500 Gr C | 50 | 62 | 345 | 428 | 0.81 | 29,000 |
| A1085 | 50 | 65 | 345 | 450 | 0.77 | 29,000 |
| A572 Gr 65 | 65 | 80 | 450 | 550 | 0.81 | 29,000 |
Strength Comparison Chart
Relative yield strength (A36 = 100%):
| Grade | Relative Fy | Relative Fu |
|---|---|---|
| A36 | 100% | 100% |
| A572 Gr 42 | 117% | 103% |
| A500 Gr B | 128% | 100% |
| A992 / A572 Gr 50 / A588 / A500 Gr C / A1085 | 139% | 112-121% |
| A572 Gr 65 | 181% | 138% |
Application Guide
W-Shapes (Beams and Columns)
| Grade | Use? | Notes |
|---|---|---|
| A36 | No | No longer produced as W-shapes |
| A992 | Yes | Standard grade for all new W-shapes |
| A572 Gr 50 | No | Not produced as W-shapes |
| A588 | No | Not produced as W-shapes |
| A500 | N/A | HSS only |
Decision: Always use A992 for W-shapes. No other option exists for new production.
Plates
| Grade | Use? | Notes |
|---|---|---|
| A36 | Yes | Economy choice for base plates, connection plates |
| A572 Gr 50 | Yes | Higher strength for girders, heavy construction |
| A588 | Yes | Weathering (unpainted) applications |
| A992 | No | Not produced as plate |
| A500 | N/A | HSS only |
Decision: A36 for economy. A572-50 for strength. A588 for weathering.
Hollow Structural Sections (HSS)
| Grade | Use? | Notes |
|---|---|---|
| A500 Gr B | Yes | Economy choice, secondary framing |
| A500 Gr C | Yes | Standard for columns, primary framing |
| A1085 | Yes | Seismic, enhanced ductility |
| A36 | N/A | Not produced as HSS |
| A992 | N/A | Not produced as HSS |
Decision: A500 Grade C for most HSS applications. A1085 for seismic.
Angles and Channels
| Grade | Use? | Notes |
|---|---|---|
| A36 | Yes | Standard grade for angles and channels |
| A572 Gr 50 | Yes | Higher strength when needed |
| A992 | No | Not produced as angles/channels |
| A588 | Yes | Weathering applications |
| A500 | N/A | HSS only |
Decision: A36 for standard applications. A572-50 for high-load members.
Weldability Comparison
| Grade | Preheat (≤3/4") | Preheat (3/4"-1.5") | Electrode | Difficulty |
|---|---|---|---|---|
| A36 | Not required | 50°F | E7018 | Easy |
| A572 Gr 50 | Not required | 50°F | E7018 | Easy |
| A992 | Not required | 50°F | E7018 | Easy |
| A588 | Not required | 50°F | E8018-W2 | Easy |
| A500 Gr B | Not required | 50°F | E7018 | Easy |
| A500 Gr C | Not required | 50°F | E7018 | Easy |
| A1085 | Not required | 50°F | E7018 | Easy |
All common US structural steels have good weldability. Preheat requirements are driven by thickness, not grade, for steels up to 50 ksi yield.
Cost Comparison
Relative cost (A36 = 100%):
| Grade | Relative Cost | Premium | Notes |
|---|---|---|---|
| A36 | 100% | — | Baseline for plates and bars |
| A572 Gr 50 | 105-110% | +5-10% | HSLA alloying (V, Nb) |
| A992 | 105-110% | +5-10% | Same as A572-50 |
| A588 | 115-125% | +15-25% | Weathering alloys (Cr, Cu, Ni) |
| A500 Gr B | 110-120% | +10-20% | Cold-formed tube process |
| A500 Gr C | 115-125% | +15-25% | Higher strength tube |
| A1085 | 120-135% | +20-35% | Enhanced quality controls |
| A572 Gr 65 | 115-130% | +15-30% | Higher alloy content |
Note: Prices fluctuate with market conditions. These premiums reflect typical mill pricing differentials, not delivered cost.
Life-Cycle Cost Considerations
| Grade | Initial Cost | Maintenance | Life-Cycle |
|---|---|---|---|
| A36 + paint | Low | Repaint every 15-25 yrs | Moderate |
| A572-50 + paint | Low-Medium | Repaint every 15-25 yrs | Moderate |
| A588 unpainted | Medium | Minimal | Lowest |
For bridges and exposed structures, A588 unpainted often has the lowest life-cycle cost despite higher initial material cost.
Grade Selection Decision Tree
For Beams
- Is it a W-shape? → A992 (only option)
- Is it a plate girder? → A572 Grade 50 (standard) or A588 (if unpainted)
- Is it an HSS? → A500 Grade C or A1085 (seismic)
For Columns
- Is it a W-shape? → A992 (only option)
- Is it an HSS? → A500 Grade C (standard) or A1085 (seismic)
- Is it a built-up section? → A572 Grade 50 (plates) with A992 (shapes if used)
For Connection Elements
- Base plates? → A36 (economy) or A572 Grade 50 (if thickness controls)
- Connection plates? → A36 (standard) or A572 Grade 50 (high-load)
- Angles and clips? → A36 (standard)
- Shear tabs? → A36 (standard) or A572 Grade 50 (high-shear)
For Exposed Structures
- Unpainted weathering steel? → A588 or A709-50W (bridge)
- Painted exposed? → Any grade (A36, A572-50, A992) with paint system
- Architectural HSS? → A500 Grade B (adequate strength, lower cost)
International Equivalents
| US Grade | Australia | Europe (EN 10025) | Canada (CSA G40.21) |
|---|---|---|---|
| A36 (Fy=36 ksi) | Grade 250 (Fy=250 MPa) | S235 (Fy=235 MPa) | 300W (Fy=300 MPa) |
| A992 (Fy=50 ksi) | Grade 350 (Fy=350 MPa) | S355 (Fy=355 MPa) | 350W (Fy=350 MPa) |
| A572 Gr 50 (Fy=50 ksi) | Grade 350 (Fy=350 MPa) | S355 (Fy=355 MPa) | 350W (Fy=350 MPa) |
| A588 (Fy=50 ksi) | — | S355J2W (weathering) | — |
| A500 Gr B (Fy=46 ksi) | C350L0 (Fy=350 MPa) | S355 (Fy=355 MPa) | 350W (Fy=350 MPa) |
| A500 Gr C (Fy=50 ksi) | C450L0 (Fy=450 MPa) | S355 (Fy=355 MPa) | 350W (Fy=350 MPa) |
Note: International equivalents are approximate. Always verify mechanical properties match the design requirements.
Calculator
Design steel members with any US grade using our free calculators:
- Beam Capacity Calculator → — Check flexural strength for any W-shape or plate girder
- Column Buckling Calculator → — AISC compression capacity with KL/r
- Bolted Connection Calculator → — Shear tab, end plate, and splice design
- Section Properties → — Full AISC section database
FAQ
Q: What is the most common steel grade in US construction? A: ASTM A992 is the most common grade for new construction. It is the standard grade for all W-shape, M-shape, and S-shape production. For plates and bars, ASTM A36 is still widely used. For HSS, ASTM A500 Grade C is the standard structural grade.
Q: Can I substitute A572 Grade 50 for A992? A: They have identical Fy (50 ksi) and Fu (65 ksi). For W-shapes, always use A992 (standard mill product). For plates and bars, use A572 Grade 50. The key difference is A992's Fy/Fu ratio requirement (0.85 max).
Q: When should I use A36 vs A572 Grade 50? A: Use A36 for base plates, connection plates, and secondary framing where economy matters. Use A572 Grade 50 for plates in welded girders, heavy columns, and high-strength applications. A572-50 costs 5-10% more but provides 39% higher yield strength.
Q: What grade should I use for seismic design? A: Use A992 for W-shape moment frames (guaranteed Fy/Fu ratio). Use A1085 for HSS moment frames (enhanced ductility). A500 Grade C is acceptable for ordinary moment frames in lower seismic regions.
Q: Is A588 worth the premium over A572 Grade 50? A: For exposed structures in suitable environments, yes. A588 eliminates painting costs ($8-15/ft² initially plus repainting every 15-25 years). The life-cycle cost of unpainted A588 is often lower than painted A572-50 over 50+ years.
Q: What is the difference between A500 Grade B and Grade C? A: Grade B has Fy=46 ksi and Fu=58 ksi. Grade C has Fy=50 ksi and Fu=62 ksi. Grade C provides 9% higher yield strength for a 5-10% cost premium. Grade C is preferred for columns and primary structural members.
Related: A36 Steel Properties → | A992 Steel Properties → | A572 Grade 50 → | A588 Weathering Steel → | A500 HSS Properties → | US Steel Grades →